大约有 48,000 项符合查询结果(耗时:0.0522秒) [XML]
How can I combine multiple rows into a comma-delimited list in Oracle? [duplicate]
...countries values ('Andorra');
insert into countries values ('Antigua');
SELECT SUBSTR (SYS_CONNECT_BY_PATH (country_name , ','), 2) csv
FROM (SELECT country_name , ROW_NUMBER () OVER (ORDER BY country_name ) rn,
COUNT (*) OVER () cnt
FROM countries)
WHE...
Checking if a SQL Server login already exists
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From here
If not Exists (select loginname from master.dbo.syslogins
where name = @loginName and dbname = 'PUBS')
Begin
Select @SqlStatement = 'CREATE LOGIN ' + QUOTENAME(@loginName) + '
FROM WINDOWS WITH DEFAULT_DATABASE=[PUBS], DEFAULT...
Cannot simply use PostgreSQL table name (“relation does not exist”)
....
In other words, the following fails:
CREATE TABLE "SF_Bands" ( ... );
SELECT * FROM sf_bands; -- ERROR!
Use double-quotes to delimit identifiers so you can use the specific mixed-case spelling as the table is defined.
SELECT * FROM "SF_Bands";
Re your comment, you can add a schema to th...
Truncate (not round) decimal places in SQL Server
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select round(123.456, 2, 1)
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How to select first and last TD in a row?
How can you select the first and the last TD in a row?
5 Answers
5
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Git in Visual Studio - add existing project?
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Just right click on your solution and select Add to source control. Then select Git.
Now your projects has been added to a local source control. Right click on one of your files and select Commit.
Then enter a commit message and select Commit. Then select Sync ...
Vim: insert the same characters across multiple lines
...as the start of a text object, which is rather useful on its own, e.g. for selecting inside a tag block (it):
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How do I find a stored procedure containing ?
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SELECT ROUTINE_NAME, ROUTINE_DEFINITION
FROM INFORMATION_SCHEMA.ROUTINES
WHERE ROUTINE_DEFINITION LIKE '%Foo%'
AND ROUTINE_TYPE='PROCEDURE'
SELECT OBJECT_NAME(id)
FROM SYSCOMMENTS
WHERE [text] LIKE...
How to drop columns by name in a data frame
..."z","u"))]
x y
1 1 2
2 2 3
3 3 4
4 4 5
5 5 6
Or, much simpler, use the select argument of the subset function : you can then use the - operator directly on a vector of column names, and you can even omit the quotes around the names !
R> subset(df, select=-c(z,u))
x y
1 1 2
2 2 3
3 3 4
4 4 ...
Can I concatenate multiple MySQL rows into one field?
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You can use GROUP_CONCAT:
SELECT person_id, GROUP_CONCAT(hobbies SEPARATOR ', ')
FROM peoples_hobbies
GROUP BY person_id;
As Ludwig stated in his comment, you can add the DISTINCT operator to avoid duplicates:
SELECT person_id, GROUP_CONCAT(DISTINCT ...
